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oxenstored: Unbounded accumulation of watches: Oxenstored maintains two datastructures about watches; one global trie, and one hashtable tracked per… (CVE-2026-79604)

0
Medium
VulnerabilityCVE-2026-79604gcveosvubuntu-cve-2026-79604cve-2026-79604ubuntu-16-04-ltsubuntu-18-04-ltsubuntu-20-04-ltsubuntu-22-04-ltsubuntu-24-04-ltsubuntu-26-10ubuntu-26-04-lts
Published: 09/08/2026 (09/08/2026, 12:00:00 UTC)
Source: GCVE Database
Product: xen

Description

A vulnerability in the Ocaml implementation of Xenstored allows unbounded accumulation of watches in two data structures, leading to unbounded memory usage and potential system-wide denial of service. This affects all Xen versions from 4.6 onwards using the Ocaml Xenstored implementation. The C Xenstored implementation is not vulnerable.

Affected software

Ubuntu:16.04:LTSmore threats →ghsa
xen
pkg:deb/ubuntu/xen?arch=source&distro=xenial
Affected versions
=4.5.1-0ubuntu1=4.5.1-0ubuntu2=4.6.0-1ubuntu1=4.6.0-1ubuntu2=4.6.0-1ubuntu4=4.6.0-1ubuntu4.1=4.6.0-1ubuntu4.2=4.6.0-1ubuntu4.3=4.6.5-0ubuntu1=4.6.5-0ubuntu1.1=4.6.5-0ubuntu1.2=4.6.5-0ubuntu1.4
Ubuntu:18.04:LTSmore threats →ghsa
xen
pkg:deb/ubuntu/xen?arch=source&distro=bionic
Affected versions
=4.9.0-0ubuntu3=4.9.0-0ubuntu4=4.9.2-0ubuntu1
Ubuntu:20.04:LTSmore threats →ghsa
xen
pkg:deb/ubuntu/xen?arch=source&distro=focal
Affected versions
=4.9.2-0ubuntu2=4.9.2-0ubuntu6=4.9.2-0ubuntu7=4.11.3+24-g14b62ab3e5-1ubuntu1=4.11.3+24-g14b62ab3e5-1ubuntu2=4.11.3+24-g14b62ab3e5-1ubuntu2.2=4.11.3+24-g14b62ab3e5-1ubuntu2.3
Ubuntu:22.04:LTSmore threats →ghsa
xen
pkg:deb/ubuntu/xen?arch=source&distro=jammy
Affected versions
=4.11.4+24-gddaaccbbab-1ubuntu2=4.16.0-1~ubuntu2=4.16.0-1~ubuntu2.1
Ubuntu:24.04:LTSmore threats →ghsa
xen
pkg:deb/ubuntu/xen?arch=source&distro=noble
Affected versions
=4.17.2-1=4.17.2+55-g0b56bed864-1=4.17.2+76-ge1f9cb16e2-1=4.17.2+76-ge1f9cb16e2-1ubuntu1=4.17.3+10-g091466ba55-1=4.17.3+10-g091466ba55-1.1ubuntu2=4.17.3+10-g091466ba55-1.1ubuntu3
Ubuntu:26.10more threats →ghsa
xen
pkg:deb/ubuntu/xen?arch=source&distro=stonking
Affected versions
=4.20.2+7-g1badcf5035-2build2=4.20.2+37-g61ff35323e-1ubuntu1=4.20.3+127-gc42374a105-1
Ubuntu:26.04:LTSmore threats →ghsa
xen
pkg:deb/ubuntu/xen?arch=source&distro=resolute
Affected versions
=4.20.0+68-g35cb38b222-1=4.20.2+7-g1badcf5035-2=4.20.2+7-g1badcf5035-2build2

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AI-Powered Analysis

Machine-generated threat intelligence

AILast updated: 10/17/2026, 23:37:43 UTC

Technical Analysis

The vulnerability in oxenstored arises because it maintains two data structures for watches: a global trie and a per-domain hashtable. When a xenbus reconnect is requested, watches are not cleared from the global trie, allowing a guest to cause unbounded memory usage in oxenstored. This can result in a system-wide denial of service. The issue affects all versions of Xen from 4.6 onwards that use the Ocaml Xenstored implementation; systems using the C Xenstored implementation are not affected.

Potential Impact

Unbounded memory usage in oxenstored can lead to system-wide denial of service conditions. This impacts availability of the affected Xen systems using the Ocaml Xenstored implementation.

Mitigation Recommendations

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or patch information is provided in the available data. Systems using the C Xenstored implementation are not vulnerable.

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Technical Details

Gcve Source
db.gcve.eu
Osv Id
UBUNTU-CVE-2026-79604
Osv Schema Version
1.7.0
Ecosystems
["Ubuntu:16.04:LTS","Ubuntu:18.04:LTS","Ubuntu:20.04:LTS","Ubuntu:22.04:LTS","Ubuntu:24.04:LTS","Ubuntu:26.10","Ubuntu:26.04:LTS"]

Threat ID: 6ad3f56e2cdf04f656662105

Added to database: 10/17/2026, 22:23:42 UTC

Last enriched: 10/17/2026, 23:37:43 UTC

Last updated: 10/17/2026, 23:37:43 UTC

Views: 2

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